Every culture has rituals for commemorating the dead. in the United States, the most common way to show that you have visited a loved one's grave is to bring flowers. However, that custom is not universal; Jews place a rock on the gravestone instead.

History

According to Rabbi Tom Louchheim, the custom of putting rocks on gravestones may have originated as a way to participate in building the gravestone (since in ancient times graves were usually marked with a cairn rather than a headstone, as we do today).

Significance

The usual explanation for this custom is that, unlike flowers, rocks are permanent, so they remain on the grave as a memento forever, and symbolize that you will never forget the deceased.

Theories/Speculation

Another theory is that this custom is not for the deceased's benefit, but for the mourner's; seeing all the rocks that other have placed upon the grave is a comfort to someone grieving for a lost loved one.

Size

The rocks are usually small, ranging from pebble-sized to golf-ball sized.

Famous Ties

An example of this custom can be seen at the end of the movie "Schindler's List," when the people Oskar Schindler saved visit his grave, and each places a stone upon it.